Study shows how lithium crowding produces faster-charging batteries

Berkeley Lab
Sally Dowd/File

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Researchers have identified why some batteries charge quickly, a discovery that could lead to better batteries for certain devices.

Published Feb. 28 in the academic journal Science, a study conducted by researchers at Lawrence Berkeley National Laboratory, or Berkeley Lab, in collaboration with New York-based Brookhaven National Laboratory, examined the charging capabilities of lithium titanate, or LTO. Researchers found that LTO displays lithium crowding, a characteristic they believe causes LTO to charge quickly. Lithium crowding occurs when lithium ions enter the LTO electrode, causing too many lithium ions to inhabit the same small area. This forces lithium ions to move throughout the LTO portion of the battery to accommodate the extra lithium ions.

According to UC Berkeley graduate student Tina Chen, a researcher at Berkeley Lab who contributed to the research, the questions campus researchers were asking included why LTO batteries charge so quickly.

Chen said Brookhaven National Laboratory’s role in the LTO research was to run many of the experiments, while Berkeley Lab’s role was to run computational simulations and compare the results to those found by Brookhaven National Laboratory. According to the study, the experiments included placing a mock LTO battery under a microscope so researchers could observe the energy levels produced by different phases of the reaction.

According to a Brookhaven National Laboratory press release, the results of this research could lead to faster-charging devices — such as cell phones and cars — that do not have to compromise on charging capacity.

LTO is a “low-voltage” material, according to Chen, so future research will be seeking high-voltage materials that also have lithium crowding. Voltage refers to the amount of energy a battery can release in the form of electricity, meaning a low-voltage battery cannot release as much energy as a high-voltage battery and is therefore less suitable for use on cars and cellphones, both of which require higher-voltage batteries.

“What we are interested in doing is finding more materials that display (lithium crowding),” Chen said. “This will fast track us into finding more fast-charging materials.”

Contact Eric Rogers at [email protected] and follow him on Twitter at @eric_rogers_dc.